<style>
    /* (行内，id, 类，标签) */
    /* (0, 0, 0, 2) */
    div div {
        color: skyblue;
    }

    /* (0, 0, 0, 1) */
    div {
        color: red;
    }
</style>

<div>
    <div>
        <div>白日依山尽，黄河入海流。</div>
    </div>
</div>